Question

我正在尝试创建一个将返回setof记录的函数。我想使用如下函数：

SELECT city_name FROM set_city(1, 1, 'ExampleName');

我的功能：

CREATE OR REPLACE FUNCTION set_city(_city_id integer, _country_id integer, _city_name varchar)
RETURNS SETOF RECORD
LANGUAGE plpgsql
as $$

DECLARE
        result record;

BEGIN
        IF EXISTS (SELECT 1 FROM geo_cities gc WHERE gc.id = _city_id)
        THEN
                UPDATE geo_cities
                SET country_id = _country_id, city_name = _city_name
                WHERE id = _city_id
                RETURNING * INTO result;
        ELSE
                INSERT INTO geo_cities(id, country_id, city_name)
                VALUES (_city_id, _country_id, _city_name)
                RETURNING * INTO result;
        END IF;
        -- It's wrong
        RETURN QUERY SELECT result;
END;
$$

我应该改变什么？

Answer 1

您可以更改return语句：

newBalance = oldBalance;

但是，返回“record”的函数需要列定义列表，因此您必须在每个查询中添加它：

...
        -- It's wrong
        -- RETURN QUERY SELECT result;
        RETURN NEXT result; -- that's good
...

实际上该函数返回SELECT city_name FROM set_city(1, 1, 'ExampleName') AS (id int, country_id int, city_name text);类型的单行，而您不需要geo_cities：

setof

请注意，您可以在单个SQL语句中获得相同的功能：

DROP FUNCTION set_city(_city_id integer, _country_id integer, _city_name varchar);

CREATE OR REPLACE FUNCTION set_city(_city_id integer, _country_id integer, _city_name varchar)
RETURNS geo_cities
LANGUAGE plpgsql
as $$
DECLARE
        result geo_cities;
BEGIN
        IF EXISTS (SELECT 1 FROM geo_cities gc WHERE gc.id = _city_id)
        THEN
                UPDATE geo_cities
                SET country_id = _country_id, city_name = _city_name
                WHERE id = _city_id
                RETURNING * INTO result;
        ELSE
                INSERT INTO geo_cities(id, country_id, city_name)
                VALUES (_city_id, _country_id, _city_name)
                RETURNING * INTO result;
        END IF;
        RETURN result;
END;
$$;

SELECT city_name FROM set_city(1, 1, 'ExampleName');

如何从函数返回setof记录？

1 个答案: